Node V12 compatible

src/WAConnection/5.Messages.ts

@@ -1,6 +1,6 @@
 import {WAConnection as Base} from './4.User'
 import fetch from 'node-fetch'
-import fs from 'fs/promises'
+import {promises as fs} from 'fs'
 import {
     MessageOptions,
     MessageType,

src/WAConnection/Utils.ts

@@ -1,7 +1,7 @@
 import * as Crypto from 'crypto'
 import HKDF from 'futoin-hkdf'
 import Jimp from 'jimp'
-import fs from 'fs/promises'
+import {promises as fs} from 'fs'
 import fetch from 'node-fetch'
 import { exec } from 'child_process'
 import {platform, release} from 'os'